Rock samples from Marion Island in the Sub-Antarctic and from the Drakensberg, South Africa were divided into sets and subjected to wetting and drying at 2 different moisture amplitudes to determine changes in physical rock properties. Rock porosity
of wetting and drying cycles is a more important factor than the degree to which the samples have been saturated; 2) changes in rock properties were detected for the control samples as well as the field samples, suggesting that the experimental techniques
used for determining the rock properties have themselves affected the samples; 3) samples that outwardly appeared very similar have responded differently to wetting and drying. This implies that even small changes in internal rock structure can have
of advance and lateral migration of the dune. Rates of advance and lateral movement varied over the period of monitoring, 1969-2012, with a decrease in rates of advance by a factor of 50%, but an increase in the rate of lateral movement. Changes in dune
behavior appear to be related to changes in wind regime and the vegetation cover of the interdune area, as a result of increased rainfall in recent years. This study demonstrates the dynamic nature of the tip of this dune and its sensitivity to changes
Aeolian features ; Aeolian transport ; Arid area ; Desert ; Dune ; Duricrust ; Environmental change ; Ephemeral stream ; Evaporite ; Geology ; Geomorphology ; Human impact ; Lithology ; Namibia ; Thematic mapping
attracted investigations of contemporary sand dune movement, hyper saline waters, evaporites and duricrusts and ephemeral flooding and recharge processes as well as environmental change and human impacts.
Rock surface temperature changes in excess of 2°C min-1 have been argued to result in permanent strain in rock. The single threshold value and the supposed importance of a rate of 2°C min-1 rock temperature change is rejected, based on lack
in minerogenic sediment input from the catchment starting around AD 1400. Changes in the seasonal distribution of rainfall during the Little Ice Age may have altered river discharge and increased erosion rates and fluvial sediment transport in pre-colonial times
formation may have resulted from ecological changes in Eilandvlei. Then, increasing sediment and nutrient flux into Eilandvlei is highlighted following the arrival of European colonists and land use change.